Inactivated Yellow Fever Virus (French Neurotropic)

Yellow fever virus (YFV) is a single-stranded, positive-sense RNA virus belonging to the genus Flavivirus in the family Flaviviridae. It is the causative agent of yellow fever, a potentially severe hemorrhagic disease endemic in tropical regions of Africa and South America. Yellow fever virus is primarily transmitted through the bites of infected Aedes or hematagami mosquitoes, which serve as both vectors and reservoirs for the virus. After entering the human host, the virus targets dendritic cells and macrophages and replicates in the cytoplasm. The viral RNA is translated into polyproteins, which are then processed to form new virions. These particles are assembled in the endoplasmic reticulum and released through the Golgi apparatus by exocytosis. The incubation period is 3-6 days, and infection can manifest with a range of symptoms, from mild fever to severe hepatitis, jaundice (hence the name "yellow fever"), and hemorrhagic shock. The virus can cause extensive liver damage, renal dysfunction, and a cytokine storm, resulting in a high mortality rate (up to 20-50% in severe cases).

YFV virions are spherical, enveloped, and approximately 40-50 nanometers in diameter. The viral genome is approximately 10.8 kilobase pairs long and encodes a polyprotein that is cleaved by host and viral proteases into three structural proteins (C, prM/M, and E) and seven nonstructural proteins (NS1-NS5). The envelope protein (E) is essential for viral entry, mediating receptor binding and membrane fusion, while the capsid protein (C) encapsidates the RNA genome. The prM protein facilitates E protein maturation and prevents premature fusion during virion assembly.